1. Field of the Invention
The present invention relates to an electric brake, and, more particularly, to an electric brake having an emergency release device, which can achieve a simplified release operation of a parking brake in an emergency situation, such as a failure or traction of the parking brake.
2. Description of the Related Art
Generally, vehicles are equipped with a variety of actuating systems or control systems for attempting to achieve their efficient operation. One of the systems is a parking brake device to keep a vehicle in a parked state or stationary state for a long time.
A most widely used example of the parking brake device is a cable parking brake device as shown in FIG. 1. The cable parking brake comprises a hinged grip 1 to be moved up and down manually while being gripped by a hand, a moving rod 3 disposed in the grip 1 to be connected, at one end thereof, to a button 2, a hinged pole 4 having one end connected to the other end of the moving rod 3, a cable 5 having one end connected to a wheel brake assembly while being secured by the pole 4, and a latch assembly 6 winding the cable 5 therearound to keep the cable 5 in a pulled state when the grip 1 is moved upward.
With the above described configuration, if a vehicle driver moves the grip 1 upward by his/her hand, the latch assembly 6 pulls the cable 5, so as to actuate the wheel brake assembly. Then, if the upward movement of the grip 1 stops, the other end of the pole 4 is engaged with the latch assembly 6 to keep the cable 5 in a pulled state. Thereby, the vehicle is kept in a stationary state.
Conversely, to release the parking brake, if the vehicle driver moves the grip 1 downward while pressing the button 2, the button 2 is displaced to move the moving rod 3 downward, thereby causing the pole 4 connected to the other end of the moving rod 3 to move downward. Thereby, the cable 5 is slackened, resulting in a release of the wheel brake assembly.
Meanwhile, the brake cable 5 is connected to an equalizer 7. This allows the same braking force to be applied to both rear wheels of the vehicle, so as to maintain a stable braking operation of the vehicle.
However, the above described conventional parking brake has an inconvenience in operation because it has to be operated manually. Accordingly, to improve the convenience of vehicle drivers, electric brakes using an electric motor have been provided recently. Examples of the electric brakes are disclosed in several documents, for example, Korean Patent Applications Nos. 10-1995-0039669 and 10-2002-0070530 and Korean Utility Model Application No. 20-2002-0015389, etc.
However, although the conventional electric parking brakes have the effect of improving the convenience of vehicle drivers, they have the risk of causing very dangerous situation and suffer from a complicated parking brake release operation because a vehicle driver or repairman should get underneath a vehicle to release the parking brake in an emergency situation, such as a failure or traction of the parking brake.